HONORS CHEMISTRYUnit 3

THIS WEEK IN HONORS CHEMISTRY

Full Semester Calendar now posted on class website!

10/12: U3L4 Elements Compounds and Mixtures

10/19: U3L9 Unit 3 Review

10/21: Unit 3 Test

Electron Orbitals(where we find electrons in the cloud)

Write the angular momentum quantum values (l) and magnetic quantum values (m) the principal quantum number, n = 3 (n= energy level of shell)

n = 3l = 0,1,2

m = -2, -1, 0, 1, 2

From the Periodic Table we know how many protons, electrons and neutrons each element has.

Use this to determine where the electrons are located in orbitals

This orbital filling map is how each electron is placed in an energy level and then a suborbital

Each suborbital holds a specific number of electrons

Electron Configurations

FOR EXAMPLE

If I know an atom has 8 electrons, what atom is it?

Oxygen

Fill the orbitals in order

8 total

1s2

8-2 = 6 remaining electrons

2s2

6-2 = 4 remaining electrons

2p4

YOU TRY

Fill Order of Periodic Table

ORBITAL DIAGRAMS

Aufbau rule – Fill from lowest energy level and work up

Pauli exclusion principal – electrons in same orbital have opposite spin and is shown by arrows in opposite directions

Hund’s rule – orbitals will fill halfway first

ORBITAL DIAGRAM EXAMPLE:K - POTASSIUM

Fill all up arrows first and then fill down arrows

per Hund’s Rule

Example – 3p4

NOBLE GAS NOTATION

Uses noble gas from previous period as start point

Ex : Na = ? in noble gas notation?

YOU TRY!

Step 1 – What is noble gas in previous period?

Step 2 – Look at last orbital filled by noble gas.

Step 3 – fill the remaining orbitals with the final electrons

WHAT IS THE NOBLE GAS NOTATION FOR SR

Kr is noble gas

Kr electron configuration is 1s22s22p63s23p63d104s24p6

Sr has 38 e and Kr has 36 so = two additional electrons to fill

5s2 is next and we have 2e -

[Kr]5s2 is the noble gas notation.

- has electron configuration periodic table

https://pubchem.ncbi.nlm.nih.gov/periodic-table/#property=ElectronConfiguration

Sortable to ionization energies, etc.